1. Field of the Invention
The invention relates generally to the field of microelectronic fabrication. More particularly, the invention relates to a device for handling semiconductor wafers during microelectronic fabrication.
2. Discussion of the Related Art
Prior art wafer handling devices, sometimes called wafer fabrication robots, are known to those skilled in the art. Wafer handling devices allow semiconductor wafers to be moved between fabrication stages and/or storage spaces in a substantially clean and pure environment to avoid contamination to the micro-circuit elements of the wafer. For example, fabricating wafers requires moving the wafer through a series of environmental or manufacturing chambers, such as etching chambers, ovens, and stepper chambers. In addition, wafers are also frequently required to be moved between and retained in storage cassettes by wafer handling devices during fabrication and subsequent storage.
Conventional wafer handling devices generally includes a mechanical arm having grippers that are each able to displace or place a wafer between manufacturing chambers and/or storage cassettes. The wafer handling devices often include rotational abilities, as well as abilities to adjust vertically and laterally to move wafers into various alignments and/or destinations. Due to the increased demand for wafers, wafer handling devices are increasingly required to accomplish wafer transportation in a faster and more cost-efficient manner. One approach employed by the known art includes simply increasing the operational speed of the wafer handling devices. However, the advantages that are attainable with faster wafer handling devices of the known art are often muted by the distance or duration between the origin and destination sites of the wafer. Therefore, what is required is a solution that also reduces the number of trips the wafer handling device must execute between any origin site and destination site.
Another problem with this technology has been that the complexity of the wafer handling devices has contributed to the operational costs for fabricating wafers. In particular, wafer handling devices are operated for long durations spanning hours, days or more, so that the presence of additional components and complexity subjects the device to fatigue and over-all wear and tear. Components such as frictional and electrical contacts formed on the wafer handling device are prone to compliance and fatigue problems which in turn shorten or interrupt the operation time for the wafer handling device. Therefore, what is also required is a wafer handling device that minimizes components, and more specifically, components subject to fatigue and failure such as coupling components and electrical connections associated with positioning the grippers.
One unsatisfactory approach in an attempt to solve the above-discussed problems involves using two or more individually driven grippers to handle and transport wafers between origin and destination sites. While this approach increases the speed at which the wafers are transported, a disadvantage of this solution is that the use of additional drivers increases the complexity of the machinery and the number of components, which in turn adds to the operational costs for manufacturing wafers and increasing the probability of down-time resulting from malfunction of added drivers. Therefore, what is required is a solution that minimizes the number of drivers used to transport two or more grippers between fabrication stages.
A primary object of the invention is to provide a simple and cost-efficient wafer handling device. Another primary object of the invention is to provide a wafer handling device capable of selectively actuating two or more grippers using one driver. Still another primary object of the invention is to provide a driver for moving grippers having a minimal number of components that are subject to failure and fatigue. Still another primary object of the invention is to provide a wafer handling device that uses magnetic coupling to position grippers for handling wafers. And another primary object of the invention is to provide a wafer handling device that uses magnetic propulsion to move grippers into and out of position for handling wafers.
Accordingly, the invention provides a wafer handling device that includes a platform having a plurality of grippers selectively moveably coupled thereto. A driver (aka carriage) is connected to the platform and controllably selectively couples to at least one of the plurality of grippers to selectively move at least one of the plurality of grippers with regard to the platform.
The invention also provides a wafer handling device that includes a first gripper that is slideably coupled to a platform so as to be moveable between a first proximal position and a first distal position. A driver (aka carriage) is movably connected to the platform and is adapted to form a first magnetic couple with the first gripper and thereby move the first gripper between the first proximal position and the first distal position.
The invention also provides a wafer handling device that includes a track assembly mounted on a platform. A carriage is slideably coupled to the track assembly. The track assembly effectuates a linear magnetic propulsion field to move the carriage between a first axial position and a second axial position. A gripper is moveably coupled to the platform and is controllably selectively coupled to the carriage to be moved from the first axial position to the second axial position.
These and other goals and aspects of the invention will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following description, while indicating preferred embodiments of the invention and numerous specific details thereof, is given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the invention without departing from the spirit thereof, and the invention includes all such modifications.